This Mentored Research Scientist Development Award (K01) application describes a career development and research plan designed to position Dr. Gilbert Kinsey as an independent investigator in immunological mechanisms of, and treatments for, kidney disease. The research focus is acute kidney injury (AKI); a significant clinical problem associated with high morbidity and mortality, which predisposes individuals to chronic and end stage renal disease. Kidney inflammation is well-established as a major pathogenic factor in AKI. Postdoctoral studies by the applicant have recently revealed that regulatory T (Treg) cells, lymphocytes known to suppress adaptive immunity, have the potential to block inflammation, acute tubular necrosis and loss of function in a mouse model of AKI. It is clear from these studies that Treg cells suppress the innate immune response in AKI, which has not been previously demonstrated. Preliminary studies showed that the ability of Treg cells to prevent innate inflammation and renal injury is dependent upon expression of adenosine 2A receptors (A2ARs) on Treg cells. We hypothesize that Treg cells modulate the innate immune response to kidney injury through suppression of a specific innate pathway involving dendritic cells, natural killer T cells and neutrophils, and that pharmacological stimulation of A2A receptors will enhance innate Treg cell functions and represent a new mode of action for A2AR agonists in kidney injury. We will elucidate: 1) the previously uncharacterized mechanism of Treg cell-mediated inhibition of the innate immune response in kidney ischemia-reperfusion injury and 2) a new mechanism of renal protection by A2AR agonists by demonstrating a causal link between Treg cell function and A2ARs. The knowledge gained from this project will reveal new aspects of Treg cell physiology and be a foundation for future pre-clinical and clinical studies to explore the therapeutic potential of regulatory T cells in AKI. Through this research plan the candidate will 1) become proficient with in vitro immunological assays to determine the mechanisms of suppression that are pertinent to kidney disease 2) gain experience with transgenic mouse technology, and 3) develop a comprehensive understanding of the physiology of Treg cells, in the context of kidney injury (from target cells, to mechanisms of suppression, to trafficking patterns during injury, to the pharmacology of an A2AR agonist and antagonist in these cells) with the ultimate goal of establishing and funding an independent laboratory focused on cures and treatments for kidney disease. The results of this research project will be used in the preparation of an independent NIH R01 application that will be submitted in the latter part of the K01 award. The career development plan includes didactic course work to equip Dr. Kinsey with advanced and comprehensive knowledge of immunology, which will complement existing knowledge of mechanisms of kidney injury. For this award, the candidate will be mentored by Dr. Mark Okusa, a recognized expert in immune mechanisms of kidney injury and the anti-inflammatory properties and potential of adenosine A2A receptor agonists in kidney disease. Assistance in planning, troubleshooting, and interpreting results will be provided by Dr. Shyr-Te Ju (consultant), an expert immunologist with extensive in vitro and in vivo expertise with Treg cells. After successful completion of this training program, Dr. Kinsey will emerge well-equipped to establish an independent career in kidney disease research. PUBLIC HEALTH RELEVANCE: Acute kidney injury incidence is increasing; between 1979 and 2002 there has been an increase in hospitalization for AKI from 35,000 to 650,000 cases per year. Treatment strategies are mainly limited to supportive care and new therapeutic interventions to prevent and treat AKI are urgently needed. Exploring Treg cell-based mechanisms of protection and therapeutic potential in pre-clinical models is essential to determine whether these cells can be used to prevent and treat kidney disease in humans.